In the aftermath of an ischemic event, the blood supply to tissues and organs distal to the blockage or occlusion is significantly diminished. Typically, an ischemic event is due to an obstruction in the vasculature or microvasculature of a mammal. A microvascular obstruction or “no reflow” phenomenon refers to inadequate myocardial perfusion through a given segment of coronary artery without angiographic evidence of mechanical vessel obstruction. Regardless of the type of obstruction, however, the result is a deprivation of oxygen to a tissue or organ downstream from the obstruction. The lack of oxygen increases the risk of necrosis of the tissues and organs.
Conventionally, a patient that has suffered an ischemic event is treated by minimally invasive catheterization, such as for example percutaneous transluminal coronary angioplasty (“PCTA”). PCTA dilates the blocked vessel and allows rapidly restoration of blood supply to the tissues and organs downstream from the blockage. It once was believed that the rapid restoration of blood flow would minimize the duration of insufficient oxygenation to the tissue and organs, such that tissue and organ survival would be optimized, i.e., reduce necrosis. However, it has recently been found that rapidly restoring the blood supply can be detrimental and often results in reperfusion injury. “Reperfusion injury” refers to damage to tissue (and/or organs) caused by the return of blood supply to the tissue (and/or organs) after a period of ischeimia. Reperfusion injury is believed to be due to a shock to the tissues and organs caused by a rapid oxygen re-saturation and abrupt changes to the pH level and blood chemistry at the site of rapid re-saturation, which can result in an overall increase in the infarct size.
Postconditioning has been found to reduce reperfusion injury. “Postconditioning” refers to a method during which the blood flow in the infarcted vessel is stopped and started for multiple cycles immediately after re-opening initial blood flow in an occluded blood vessel, such as from a ST segment elevation myocardial infarction (“STEMI”). Currently, physicians perform postconditioning techniques using a conventional angioplasty catheter because, currently, there is no device on the market that is specifically designed to perform postconditioning techniques. A conventional angioplasty balloon catheter is not optimized to sequentially inflate and deflate for multiple cycles.
Further, the local delivery of beneficial agents to into a lumen is known. Currently, beneficial agents can be delivered locally within a lumen by a rapid exchange balloon catheter, over-the-wire catheter, or perfusion catheter. There is no device on the market that exists designed for enhanced reperfusion and further, adapted, to locally deliver a beneficial agent to synergistically improve inhibition of reperfusion injury. Thus, a method and a catheter system designed to enable multiple cycles of sequential inflation and deflation and deliver beneficial agent is needed.